Option to disable HTML support or add exceptions for misformed HTML

**Is your feature request related to a problem? Please describe.**
I'm parsing markdown from the Azure DevOps wiki. MS adds some useful features to markdown, such as at-mentioning people (where they get an email notification) 👍. Unfortunately, they picked syntax similar to actual HTML which conflicts with how markdown is typically parsed 👎

```
TODO: @ do this
```

The angle brackets trip up the editor and leads to the rest of the document being formatted incorrectly (or I suppose, still correctly, depending on your vantage point).


**Describe the solution you'd like**
Ignore HTML tags we don't recognize or are misformed.

**Describe alternatives you've considered**
- Acceptable but much less great: Opt-in config to disable HTML parsing altogether
- Ability to provide custom markdown parsing (but this is likely too much work for this enterprise app and I'd probably move on without this)